1. Field of the Invention
This invention relates to the general field of balloons used for other than scientific or conveyance purposes; i.e. the field of those used for decorative, novelty, advertising or amusement purposes.
2. Brief Description Of The Prior Art
Balloons of all sorts have been used for many years for decorative, novelty, advertising and amusement purposes, and such balloons have been fabricated in a variety of shapes, have been adorned with various types of attachments, have been made with multicolored materials, and have had printed on them a wide range of messages, greetings, designs and the like. The materials out of which they have been constructed, however, have not varied to any significant extent. That is to say, most such balloons are simply seamless vessels fabricated of elastomeric materials into which a gas such as air or helium is discharged in order to inflate the vessel, therefore stretching it to many times its uninflated size.
One characteristic of these elastomeric materials is, however, a permeability to lighter than air gases, such as the helium commonly used to inflate such balloons to give them buoyancy in air. As a result, balloons of the sizes normally employed for the recited purposes ordinarily lose their buoyancy within a matter of hours. More significantly, balloons made of such elastomeric materials may, even if uniform in uninflated size, be inflated with varying amounts of air or other gas, depending on the degree to which the material is stretched during inflation.
More recently, however, a popular type of balloon used for these purposes has been the so-called "permanently buoyant" type. Rather than being constructed as a seamless vessel of elastomeric material, the permanently buoyant balloon is constructed as a substantially gas impermeable envelope filled with a lighter than air gas at about atmospheric pressure. Ordinarily, this envelope is formed of sheets of a composite material which are continuously sealed along their edges, and which have a continuous opaque coating of vapor deposited aluminum on at least one side. These composite materials have at least one nonelastomeric polymer film layer, and balloons so constructed are therefore not subject to stretching when inflated.
Among the nonelastomeric polymer materials known in the prior art for use in the at least one film layer of such ballons are polyolefins, such as polyethylene and polypropylene; polyvinylidene chloride (saran); polyester; polyvinyl chloride (PVC); cellophane; polyvinyl alcohol (PVA); regenerated cellulose; polyurethane; ethylene vinyl acetate copolymer (EVA); polyamides and polynitriles.